Pre/Post-Heating System Control Unit; Unscrew Glow Plugs And Remove Them From The Cylinder Head - Opel Zafira B MPV 2006 Owners Workshop Manual

4 Undo the two retaining bolts, disconnect the
four vacuum hoses and remove the vacuum
pipe assembly from the top of the camshaft
cover.
5 Disconnect the fuel leak-off hose
connection at each fuel injector by pushing in
the locking clip and lifting out the hose fitting.
Suitably plug or cap the leak-off hose union
on each injector, and slip a plastic bag over
the disconnected leak-off hose to prevent
dirt entry. Release the leak-off hose from
the plastic support bracket on the intake
manifold.
6 Release the retaining clips and disconnect
the two fuel return hoses at the fuel return
damping chamber. Suitably plug or cover the
open unions to prevent dirt entry.
7 Disconnect the fuel return hose quick-
release fitting, then undo the two bolts and
remove the damping chamber. Suitably plug
or cover the open unions to prevent dirt entry.
8 Disconnect the wiring from the glow plugs
by squeezing the connectors with thumb and
forefinger, and pulling them from the plugs.
9 Unscrew the glow plugs and remove them
from the cylinder head (see illustration).
DOHC (Z19DTH} engines
10 The glow plugs are located at the rear of
the cylinder head above the intake manifold.
To gain access, remove the windscreen cowl
panel as described in Chapter 11.
11
Remove the plastic engine cover by
pulling it upwards off the mounting studs.
12 Disconnect the wiring from the glow plugs
by squeezing the connectors with thumb and
forefinger, and pulling them from the plugs.
13 Unscrew the glow plugs and remove them
from the cylinder head (see illustration 17.9).
Starting and charging systems 5A•9
Inspection
14 Inspect each glow plug for physical
damage. Burnt or eroded glow plug tips can
be caused by a bad Injector spray pattern.
Have the injectors checked if this type of
damage is found.
15 If the glow plugs are in good physical con-
dition, check them electrically using a 12 volt
test lamp or continuity tester as described in
the previous Section.
16 The glow plugs can be energised by
applying 12 volts to them to verify that they
heat up evenly and in the required time.
Observe the following precautions.
a) Support the glow plug by clamping it
carefully in a vice or self-locking pliers.
Remember it will become red-hot.
b) Make sure that the power supply or test
lead incorporates a fuse or overload trip
to protect against damage from a short-
circuit.
c) After testing, allow the glow plug to cool
for several minutes before attempting to
handle it.
17 A glow plug in good condition will start
to glow red at the tip after drawing current
for 5 seconds or so. Any plug which takes
much longer to start glowing, or which starts
glowing in the middle instead of at the tip, is
defective.
Refitting
18 Carefully refit the plugs and tighten to the
specified torque. Do not overtighten, as this
can damage the glow plug element. Push
the electrical connectors firmly onto the glow
plugs.
19 The remainder of refitting is a reversal of
17.9 Unscrew the glow plugs and remove
them from the cylinder head
removal, checking the operation of the glow
plugs on completion.
Removal
1 The pre/post-heating system control unit
is located on the left-hand side of the engine
compartment where it is mounted onto the
front of the battery tray.
2 Remove the battery as described in Sec-
tion 4.
3 Unclip the control unit and slide it up and
off the battery tray (see illustration 4.10).
4 Disconnect the wiring connector from the
base of the control unit and remove the unit
from the engine compartment.
Refitting
5 Refitting is a reversal of removal.